The subject matter disclosed herein relates to refrigeration systems. More specifically, the subject matter disclosed herein relates to refrigeration of cargo compartments of trucks or trailers.
A typical refrigerated truck or truck trailer, such as those utilized to transport a cargo, includes a refrigeration unit located at one end of the cargo compartment. The refrigeration unit includes a compressor, condenser, expansion valve and evaporator serially connected by refrigerant lines in a closed refrigerant circuit in accord with known refrigerant vapor compression cycles. The evaporator is located in a compartment that requires cooling, such as a cargo compartment of the truck or trailer. The condenser and compressor are located outside of the compartment. Cargo compartment air is passed over the coils of the evaporator, boiling the refrigerant flowing through the evaporator coil, thus heat is absorbed from the air in the conditioned compartment to cool the conditioned compartment. The gaseous refrigerant is then flowed to the compressor for compression thereat. A power unit, including an engine, drives the compressor of the refrigeration unit, and is typically diesel powered, or in other applications natural gas powered. In many truck/trailer transport refrigeration systems, the compressor is driven by the engine shaft either through a belt drive or by a mechanical shaft-to-shaft link. In other systems, so-called “electrically driven” systems, the engine drives a generator that generates electrical power, which in turn drives the compressor.
Exhaust gas from the engine is directed outwardly to ambient via an exhaust pipe. The exhaust gas temperature from the engine can be quite high, especially from natural gas powered engines, where the exhaust gas temperature can exceed 1000° Fahrenheit. This is problematic when the exhaust is directed toward, for example, foliage or sidewalks, nearby vehicles or the like and may result in fire or damage.